An organic semiconductor material having an electric charge (electron and hole) transport property is expected to be applied to an organic photoelectric conversion element (such as an organic solar cell and a photosensor), and an organic photoelectric conversion element such that a fullerene compound and a conjugated polymer are used as an electron acceptor and an electron donor respectively has been studied in recent years.
For example, Patent Document 1 discloses an organic photoelectric conversion element containing methyl[6,6]-phenyl-C71-butyrate ([70]PCBM) as a C70 fullerene compound and poly[2-methoxy-5-(3′,7′-dimethyl-octyloxy)-p-phenylene-vinylene]. Nonpatent Document 1 discloses an organic photoelectric conversion element containing 3′-(3,5-bis-trifluoromethylphenyl)-1′-(4-nitrophenyl)pyrazolino[70]fullerene (BTPF70)) as a C70 fullerene compound and a fluorene copolymer represented by the following formula.
    [Patent Document 1] Japanese translation of a PCT application No. 2006-518110    [Non-patent Document 1] Advanced Functional Materials, Vol. 15 (2005), 1665-1670